The present invention relates to liquid drainage systems, and more particularly to sampling ports for such systems.
Closed drainage systems have been utilized to drain urine from the bladder of a patient in the following manner. A catheter is inserted through the urethra of the patient until a distal end of the catheter containing a drainage eye is located in the bladder, and a retention balloon is inflated through an inflation lumen to retain the catheter in place in the patient. An upstream end of a drainage tube is connected to a proximal end of the catheter which extends outside the patient's body, and a downstream end of the drainage tube communicates with a drainage or collection bag. With the drainage system in place, urine drains from the bladder through the drainage eye, a lumen in the catheter, and a lumen in the drainage tube to the drainage bag where the urine is collected.
Periodically it is desirable to obtain a fresh sample of urine from the closed system for analysis. The sample must be obtained in a manner without affecting the closed nature of the system, since bacteria may otherwise be introduced into the system resulting in possible infection and harm to the patient. In the past, samples have often been obtained by obstructing the proximal end of the catheter, such as by hemostat, after which a needle is punctured through the wall of the catheter, and the urine sample is withdrawn from the catheter lumen through use of a syringe attached to the needle. It has been found that such a procedure is unsatisfactory, since the needle puncture leaves a hole in the sidewall of the catheter. In certain of the catheters, such as a plastic or silicone catheter, the sidewall of the catheter does not seal around the hole thus exposing the catheter lumen to the atmosphere. In other catheters, such as a latex catheter, the hole may be initially sealed, but when the catheter is stretched or bent during subsequent use of the system, the hole may be opened such that the interior of the system is exposed to the atmosphere, which may result in contamination of the closed system. Also the needle may inadvertently puncture the inflation lumen of the catheter, resulting in deflation of the retention balloon.